Archimedes Screw and Crinoid Plate

Expertly prepped and from Indiana! One half of this plate is a series of fossil Archimedes Screws and the other a rare crinoid stem with head. The Archimedes Screw is a variety of bryozoa.  This Mississippian aged specimen is an excellent example of the ancient sea floor that once covered the Midwest US. This specimen about 11x11x1.5 at the widest points and weighs 11 pounds. It will require special packaging.